I'm not on WW, but in nu4you as part of the Weight Loss Challenge, I would just log it as how I ate it.
If you don't log what you eat properly, the only one who's cheated is you.
Track your consumption appropriately, and count any "hiccups" as a learning experience. In this case, I bet you always remember to order skim from here on out!
EDIT: And a rule I've applied when eating out is to always assume it's the fattiest meat, whole milk or heavy cream, and butter that's used to prepare your food. You won't hurt your program if you overestimate your fat intake!